       Document 0779
 DOCN  M9640779
 TI    Detection of T cell CD4 epitopes in HIV-infected individuals.
 DT    9604
 AU    Kunkl A; Valle MT; Fenoglio D; Dodi F; Morandi N; Rizzo F; Manca F;
       Department of Immunology, San Martino Hospital, Genoa, Italy.
 SO    Eur J Histochem. 1994;38 Suppl 1:41-6. Unique Identifier : AIDSLINE
       MED/96120978
 AB    HIV antigens can be detected in the circulation of HIV-infected patients
       and are associated with active virus production. Free virions and
       shedded gp120 bind CD4 with high affinity. We have studied the
       expression of Leu3a and OKT4 epitopes on a CD4+ T cell line (HPB-ALL),
       pretreated with HIV rgp120, and on CD4+ pheripheral blood T lymphocytes
       of HIV-infected patients. The associated determination of these epitopes
       (the Leu3a mapping at the gp120 binding site of CD4 and the OKT4 mapping
       at a site independent of gp120 binding) allowed to monitor binding of
       gp120 to surface CD4 and maintenance of CD4 expression. The comparison
       of MFI of gp120-treated versus untreated Leu3a+ HPB-ALL cells suggested
       that the Leu3a epitope was masked by treatment with 20 micrograms/ml
       rgp120, while with 1 microgram/ml rgp120 masking was undetectable,
       although gp120 was bound to cells. The determination of the Leu3a and
       OKT4 epitopes in 105 HIV-infected individuals and in 50 normal controls,
       showed that the Leu3a epitope is detected equally well in HIV-infected
       and in normal subjects, provided the anti-Leu3a is used at saturation.
       Therefore the binding to epitopes distinct from the gp120-binding site
       does not seem to be a requisite for the selection of anti-CD4 mAbs for
       immunophenotyping. To optimize the detection of CD4 masking, a limiting
       amount of conjugated anti-Leu3a has to be used. Measurements of CD4
       binding by gp120 in terms of gp120-free CD4 molecules, as detected by
       reactivity with anti-Leu3a, may be used to monitor disease progression
       in HIV-infected subjects.
 DE    Acquired Immunodeficiency Syndrome/IMMUNOLOGY  Antibodies,
       Monoclonal/DIAGNOSTIC USE/IMMUNOLOGY  AIDS-Related Complex/IMMUNOLOGY
       Binding Sites, Antibody  Cell Line  CD4-Positive
       T-Lymphocytes/*IMMUNOLOGY  Disease Progression  Epitopes/IMMUNOLOGY
       Human  HIV Envelope Protein gp120/IMMUNOLOGY  HIV Infections/*IMMUNOLOGY
       Immunophenotyping  Support, Non-U.S. Gov't  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

